A vehicle seat may include a side airbag that deploys from a side of the seat forward along a side of an occupant during a vehicle impact. In the inflated position, the side airbag inflates along the crest of the pelvic bone, the soft tissues above the pelvic bone, and the lower rib cage. Vehicles may include armrests adjacent the seat. For example, the armrest may be mounted to the seat or to the floor adjacent the seat and may extend upwardly along the side of the seat. The space occupied by the armrest and the space occupied by the airbag in the inflated position may create competing design factors in the design of the seat to ensure that the armrest is in a desired position and does not inhibit the inflation of the side airbag.